Approving a Duo Push on iOS Causes "NSURLErrorDomain" Error


University of Michigan Duo Mobile


When trying to approve a Duo push, or add a Duo account to your iOS device (iPhone, iPad), you receive the error: NSURLErrorDomain - 1003 or 999 or 1200. (This could be any of several different numbers.) 


NSURL is a legacy API on iOS devices and can prevent Duo Mobile from achieving adequate network connectivity.  The error typically means that it can't communicate with a server. 

To resolve the error, try the following troubleshooting steps:

  • Switch to an alternative WiFi network and try again
    • If you are on the MGuest network, forget the network in settings, switch to MWireless and try again
  • Turn off WiFi to force your device to use cellular data, and try again
  • Update to the latest version of iOS and try again

Additional Information

Need additional information or assistance? Contact the ITS Service Center.


Article ID: 8911
Wed 9/21/22 2:22 PM
Thu 1/5/23 4:18 PM